1. Field of the Invention
The present invention relates to a network management system that manages switching equipment in a network, and in particular to a scheduling technique of traffic data collection from the switching equipment.
2. Description of the Related Art
A network management system performs maintenance and administration of a switched network, for example, monitoring failures in the switched network, changing the setting of a switch, and monitoring the traffic status of each switch.
In general, a switch is provided with a traffic detector or counter for each line port to measure the amount of traffic thereon and the network management system collects the traffic data measured for each line port from a switch at regular intervals.
However, in the case of a large-size electronic switching system, 1000 traffic counters are installed therein. If traffic data is concurrently read from all the 1000 traffic counters, then the switching system becomes overloaded, which may cause the line connection function notto normally work. For example, when the traffic data collection is performed, line connections cannot be made even when there are available lines, resulting in increased loss of call.
An object of the present invention is to provide a network management system and a traffic data collection method that perform traffic data collection so as not to overload switching equipment.
According to the present invention, a network management system having a function of collecting traffic data at predetermined intervals from a switch having a plurality of traffic detectors provided for respective ones of line ports of the switch, includes: a schedule table having a plurality of entries, in which traffic data collection events for respective ones of the traffic detectors are distributed at first predetermined intervals; a scheduler for creating the schedule table at second predetermined intervals; and a traffic data collection processor for sequentially accessing the plurality of entries of the schedule table to transmit traffic data collection requests to the traffic detectors depending on whether a traffic data collection event is registered in an accessed entry.
The entries in the schedule table may be associated with lapses of time in sequence, respectively. A number N of the entries in the schedule table may be determined by multiplying M by T, where M is a maximum permissible number of traffic data collection requests that the switch can cope with per unit of time, and T is a second predetermined interval. A first predetermined interval L may be determined by dividing N by K, where K is a number of the traffic detectors provided in the switch.
The traffic data collection events may be registered in equally spaced entries in the schedule table. At least one interrupt event other than the traffic data collection events may be registered in an available entry other than the equally spaced entries in the schedule table. The scheduler may delete said at least one interrupt event from the schedule table when all the entries of the schedule table have been accessed. Each of the equally spaced entries in the schedule table may store an event type of traffic data collection and an identification identifying a corresponding traffic detector.
According to another aspect of the present invention, a method for collecting traffic data at predetermined intervals from a switch having a plurality of traffic detectors provided for respective ones of line ports of the switch, includes the steps of: storing a plurality of entries in a schedule table, in which traffic data collection events for respective ones of the traffic detectors are distributed at first predetermined intervals; creating the schedule table at second predetermined intervals; and sequentially accessing the plurality of entries of the schedule table; and when a traffic data collection event is registered in an accessed entry, transmitting a traffic data collection request to a corresponding traffic detector.
According to still another aspect of the present invention, a network management system having a function of periodically collecting traffic data at predetermined intervals from a switch having a plurality of traffic counters provided for respective ones of line ports of the switch, includes: traffic counter processors provided for respective ones of the traffic counters, each of the traffic counter processors transmits a traffic data collection request to a designated one of the traffic counters and stores traffic data received from the designated traffic counter; a schedule table for scheduling operations of the traffic counter processors; a schedule table creation processor for providing a schedule time interval to each of the entries of the schedule table and assigning processor identifications of the traffic counter processors to entries equally spaced in the schedule table; a collection cycle timer for activating schedule table creation processing of the schedule table creation processor in a predetermined period of time; a schedule execution processor for activating the traffic counter processors depending on the processor identifications registered in the schedule table; and a schedule execution timer for activating the schedule execution processor in a predetermined period of time, wherein traffic counter collection requests are transmitted to the switch uniformly for a predetermined time period.
As described above, a predetermined number of traffic data collection requests are transmitted to the switch at predetermined intervals, which are equally spaced during a predetermined time period. Therefore, the load of traffic data collection on the switch is distributed, avoiding causing the switch to be overloaded. The distribution of traffic data collection requests is obtained by a schedule table containing a plurality of entries according to elapsed time, among which a plurality of events are distributed.